1. Field of the Invention
The present invention relates to the field of surgery and, more particularly, to an improved rib retractor for accessing the interior of a patient's chest. One blade of the rib retractor is raised by an external lifting device relative to the other blade so that the surgeon has an increased field of vision and improved access into the patient's chest cavity.
2. Background Art
Atherosclerosis or coronary artery disease is among the most common and serious health problems confronting the medical profession. In the past, many different approaches for bypass grafting have been used to surgically correct occluded or stenosed coronary arteries. The approaches all require that the surgeon retract bone structures to access the operative site.
A sternotomy is probably the most common procedure performed today for providing surgical access to the heart and coronary arteries. A sternotomy, however, is highly invasive. The patient's skin is incised at the midline overlying the chest and the sternum is cut along its entire length. The cut edges of the sternum are spread with metal retractors, exposing a large cavity to allow surgery to be performed on the heart. Generally, such retractors use two substantially perpendicular retractor blades that remain generally at the same height in their operative position. This orientation of the blades limits the surgeon's mobility and access to the surgical field, especially for procedures performed deep within the thoracic cavity.
Also, conventional bypass graft surgery usually requires that the heart be stopped and the patient be placed on a heart/lung bypass machine during the procedure. This occurs at considerable expense and risk to the patient.
Bypass grafts are often needed that use homologous tissue, so the surgical procedure also requires grafting the patient's saphenous vein. Unfortunately, the patient often suffers complications at the graft donor site that are worse and more painful than the sternotomy. Use of alternative graft vessels, such as the internal mammary artery ("IMA") which runs along the underside of the rib cage, greatly reduce the trauma to the patient. Coronary bypass procedures thus preferably use a retraction apparatus for exposing the IMA. The retraction apparatus should elevate one side of the rib cage to facilitate reaching the IMA.
In an effort to reduce the expense, risk, and trauma to the patient, physicians have recently turned to minimally invasive surgical approaches to the heart, such as intercostal and endoscopic access to the surgical site. Thoracoscopic techniques allow access to the heart from a lateral approach. Incisions are formed in intercostal sites on one side of the chest to give access to the heart. Such a procedure, in contrast to the sternotomy, is less traumatic and allows the surgical procedure to be performed on a beating heart. Additionally, the patient's recovery time is reduced for single and double bypass procedures, especially when the IMA is used for grafting.
A primary problem with thoracoscopic procedures is achieving sufficient area to perform the surgery, particularly since the entry access is limited to the space between ribs. Accordingly, retractors are used to spread apart two adjacent ribs. Since the maximum possible separation between ribs is limited, it is also advantageous to lift one of the spread ribs relative to the adjacent rib.
One example of creating additional space within the rib cage is a device disclosed in U.S. Pat. No. 5,676,636, entitled "Method for Creating a Mediastinal Working Space." This disclosed device does not spread the ribs, but instead lifts the rib cage to increase the working space for cardiac surgery. Accordingly, this device does not create a "tunnel" that increases the surgeon's field of view, nor does it facilitate grafting the IMA.
Another attempt to address this problem with the limited field of view is disclosed in European Patent Application 792,620, entitled "Access Platform for Internal Mammary Dissection." The disclosed retractor provides two blades to spread adjacent ribs. However, the retractor uses a device, which is permanently connected to the retractor, to lift one rib relative to the other. The lifting member contacts a portion of the patient's body to exert the downward force to produce the opposed upward force to lift the rib. Accordingly, the lifting member can be difficult to use on obese patents and can cause bruising and post-surgery pain for all patients.
Prior to the present invention, there has not been a retractor designed especially for the narrow window presented via an intercostal thoracotomy approach that overcomes the above disadvantages of the prior art. Prior to the present invention, there existed a need in the art for a rib retractor that would increase the surgical access field without relying on a design that pushes downwardly against the patient's body. There also existed a need for a retractor that exposes the IMA.